Secondary galvanizing pretreatment process for electroplating nickel on surface of magnesium alloy

A nickel electroplating and pretreatment technology, applied in the coating process of metal materials, etc., can solve problems such as complex process, polluted environment, and poisonous plating solution, and achieve high corrosion resistance, beautiful appearance, and high bonding force between the substrate and the coating Effect

Inactive Publication Date: 2014-07-02
无锡市锡山区鹅湖镇荡口青荡金属制品厂
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the process is complicated, the repeatability is poor, cyanide is used, the plating solution is poisonous, pollutes the environment, the brightness of the coating and the stability of the plating solution need to be further improved
[0004] In order to overcome the shortcoming of complex process, researchers have developed a direct electroless nickel plating method, such as JP2003073843, which uses chromic anhydride to etch magnesium alloys, performs electroless nickel plating after fluoride activation, and adjusts the electroless nickel plating solution with ammonia water to make it appear Weakly alkaline, once obtained the chemical nickel plating layer with good bonding force and high corrosion resistance, Li Degao et al. used deflocculation → chemical degreasing → light emission → neutralization → activation → pre-treatment in the patent CN1699634A magnesium alloy electroplating method The galvanizing process has obtained a relatively good pre-galvanized layer, and the pre-galvanized solution is cyanide-free, non-toxic and harmless. In the patent CN1737205A, people such as Yang Sheng pickled the magnesium alloy with concentrated hydrofluoric acid (11%) Afterwards, directly electroplate aluminum to obtain a relatively good aluminum coating. Chinese patent CN1641075A has described in detail the surface or activation treatment methods and surface plating methods of magnesium and magnesium alloys. Although these processes are all separated from cyanide electroplating, the treatment before electroplating The process is mostly based on the improvement of the DOW process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] A secondary galvanizing pretreatment process for electroplating nickel on the surface of magnesium alloys, the process includes two steps of galvanizing and electrogalvanizing, wherein:

[0014] Zinc dipping: The zinc dipping solution is composed of: zinc sulfate 32g / L, potassium pyrophosphate 210g / L, sodium carbonate 8g / L, potassium fluoride 5g / L; ammonium bifluoride 2g / L, and the balance is water; the process is: pH Value: 10.5-11.0, temperature: 63-65°C, time: 3min;

[0015] Electro-galvanizing: Electro-galvanizing bath composition: ZnSO 4 ·7H 2 O32g / L, K 4 P 2 o 7 ·3H 2 O168g / L, KF18g / L, C 6 h 17 o 7 N 3 32g / L, phytic acid 0.6g / L, H 2 CSNH 2 : 4g / L, the balance is water; the process is: use pure zinc as the anode, electroplating temperature: 35-45℃, electroplating time 30min, current density: 2-3A / dm 2 .

Embodiment 2

[0017] A secondary galvanizing pretreatment process for electroplating nickel on the surface of magnesium alloys, the process includes two steps of galvanizing and electrogalvanizing, wherein:

[0018] Zinc dipping: The composition of the zinc dipping solution is: zinc sulfate 36g / L, potassium pyrophosphate 200g / L, sodium carbonate 10g / L, potassium fluoride 3g / L; ammonium bifluoride 3g / L, and the balance is water; the process is: pH Value: 10.5-11.0, temperature: 63-65°C, time: 3min;

[0019] Electro-galvanizing: Electro-galvanizing bath composition: ZnSO 4 ·7H 2 O36g / L, K 4 P 2 o 7 ·3H 2 O164g / L, KF20g / L, C 6 h 17 o 7 N 3 32g / L, phytic acid 0.6g / L, H 2 CSNH 2 : 4g / L, the balance is water; process: use pure zinc as the anode, electroplating temperature: 35-45℃, electroplating time 40min, current density: 2-3A / dm 2 .

Embodiment 3

[0021] A secondary galvanizing pretreatment process for electroplating nickel on the surface of magnesium alloys, the process includes two steps of galvanizing and electrogalvanizing, wherein:

[0022] Zinc dipping: The composition of the zinc dipping solution is: zinc sulfate 34g / L, potassium pyrophosphate 205g / L, sodium carbonate 9g / L, potassium fluoride 4g / L; ammonium bifluoride 2.5g / L, and the balance is water; the process is: pH value: 10.5-11.0, temperature: 63-65°C, time: 4min;

[0023] Electro-galvanizing: Electro-galvanizing bath composition: ZnSO 4 ·7H 2 O34g / L, K 4 P 2 o 7 ·3H 2 O166g / L, KF19g / L, C 6 h 17 o 7 N 3 33g / L, phytic acid 0.5g / L, H 2 CSNH 2 : 5g / L, the balance is water; process: use pure zinc as the anode, electroplating temperature: 35-45℃, electroplating time 35min, current density: 2-3A / dm 2 .

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PUM

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Abstract

The invention discloses a secondary galvanizing pretreatment process for electroplating nickel on the surface of magnesium alloy. The secondary galvanizing pretreatment process comprises two steps of: zinc galvanizing and zinc electroplating. The pretreatment process disclosed by the invention has the advantages that pretreatment for nickel electroplating is carried out by adopting a secondary zinc galvanizing and coating process of zinc immersion and zinc electroplating, and by adjustment of the components for zinc immersion and zinc electroplating solution, components with toxicity and high pollution are not adopted, so that the plating process is environmentally friendly and safe and provides good basic plating layer for the following nickel plating.

Description

technical field [0001] The invention relates to the technical field of electroplating, in particular to a secondary galvanizing pretreatment process for electroplating nickel on the surface of a magnesium alloy. Background technique [0002] As a lightweight engineering structural material, magnesium alloy has high specific strength, high specific stiffness and superior shock absorption performance, and has a wide range of applications in transportation, communication, aviation, aerospace and other fields. However, magnesium alloys have high chemical activity, low electrode potential, and loose oxide film on the surface, resulting in low protection performance, which restricts the application and development of magnesium alloys. This has aroused people's attention to the surface corrosion and protection of magnesium alloy parts, and a lot of research has been done on the surface of magnesium alloys, such as anodic oxidation, chemical conversion film, organic coating, surface...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/42C23C22/36C25D3/22
Inventor 钱永清
Owner 无锡市锡山区鹅湖镇荡口青荡金属制品厂
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